A symbol is an object, a sound or an image that represents another object, sound, idea, entity, belief or action. Symbols have been used throughout history for many purposes, both magical and mundane. Symbols are seen everywhere in our world. Alphabets are symbols that represent sounds and in some cases, ideas and they can be combined to represent other ideas and sounds. Numerals are symbols that represent quantities and, for some, ideas. Musical notes are symbols for sounds. The shapes and colors of street signs and lights become connected with the ideas they represent so that we know that a red octagon means stop, even if the word (also a symbol) is not written on it because the shape and color itself have become a symbol for the idea.